Been trying to research the same issue. From what I've ascertained the Ameriglos are a nice budget sights almost as good as the Trijicon HDs. TFOs have a rep for being a little fragile and aren't quick in between light and dark.
The glock guys who run Ameriglos swear the way to go is the pro I dots with the yellow back, makes you pick up the front way easier, but unfortunately they do not sell this configuration (yet) for the M&P. Same with the TFOs, yellow rears are supposed to be the way to go, makes the front stand out, but gives the rears enough to make out.
I'm currently suffering paralysis by over analysis, but I'll likely end up going with the orange HDs.